During use, many electrical components generate heat and for proper functioning of the electrical components, it is necessary to remove the heat from the component. Among the means of accomplishing this heat transfer have been suggested, especially for small electronic modules, such as those containing integrated circuit chips, thermally conductive greases or radial finger contacts that shunt the heat from the chip to the cap present to protect the chip.
Integrated circuit modules generally include a cap portion to protect the integrated circuit chip. A typical configuration of an integrated circuit module can be found, for example, in U.S. Pat. No. 4,233,620 to Darrow, et al. and assigned to the assignee of the present application, disclosure of which is incorporated herein by reference.
In order to facilitate removal of heat from the integrated circuit chip, a thermally conductive grease can be applied between the integrated circuit chip and the cap. The thermally conductive grease is usually in direct contact with the integrated circuit chip(s) and cap. Heat generated from the integrated circuit chip during use is conducted from the integrated circuit chip by the grease to the module cap; whereafter, it is dissipated into the ambient surroundings.
Thermally conductive greases for this purpose are well-known and typically they contain a liquid carrier and a thermal filler to increase heat conduction. In addition, other components for specific purposes such as to thicken the grease or remove moisture from the grease can be added.
An improved thixotropic, thermally conductive material is disclosed in U.S. Pat. No. 4,265,775 to Aakalu, et al., and assigned to the assignee of the present application, disclosure of which is incorporated herein by reference. The thermally conductive materials disclosed therein overcome a number of problems that occurred in prior greases. Although the thixotropic, thermally conductive material disclosed in U.S. Pat. No. 4,265,775 is quite suitable for its intended purpose, such material is very difficult to apply due to its viscosity and its inherent high adhesive and cohesive forces. In particular, these greases are normally squeegeed in relatively thick increases the assembly loads on the module and, in some instances, tends to cause damage to the chip when applied to the chip.